1. Field of the Invention
This invention relates to an image signal recording system for recording image signals on a recording medium.
2. Description of the Related Art
An electronic still video camera system has been known as an image signal recording and reproducing system for recording and reproducing image signals on and from a recording medium.
The electronic still video camera system is arranged to use a magnetic disc measuring two inches in diameter. One field amount of still image signal is recorded in each of 50 recording tracks formed in a concentric state on the magnetic disc after the following processes: The luminance signal component of the image signal is frequency-modulated. The color-difference signal components of two different kinds of the image signal are converted into a color-difference line-sequential signal component and, after that, are also frequency-modulated. The two frequency-modulated signal components thus obtained are frequency-multiplexed into a recording image signal before recording. One field amount of the recording image signal thus obtained is recorded in each recording track on the recording medium. The recorded image signal is reproduced by performing a converting action in a manner reverse to the converting action performed in recording the image signal.
The electronic still video camera system has two different modes of operation for obtaining two different recording formats. One is a field recording and reproducing mode in which one field amount of still image signal forming one picture of still image is recorded and reproduced in and from one recording track, so that the number of still images recordable on one magnetic disc can be increased. The other is a frame recording and reproducing mode in which one frame amount, corresponding to two field amounts, of still image signal forming one picture of still image is recorded in two recording tracks with one field recorded in one recording track and the other field recorded in the other recording track. Though the number of recordable still images on one magnetic disc decreases to half, the still images can be recorded and reproduced with a higher picture quality.
As mentioned above, the electronic still video camera system is arranged to record one picture amount of still image signal in two recording tracks on the magnetic disc in the above-stated frame recording and reproducing mode. In this mode, therefore, a maximum number of recordable frame image signals is only for 25 pictures while the number of recordable tracks on one magnetic disc is specified to be 50 for the format of the electronic still video camera system. The conventional still video camera system thus has presented a problem in respect to economy.